Breathing Hot Air

Breathing cold air makes you cold. This simple tidbit is the underlying principle of the Polarwrap Exchanger, the most high-tech facemask you've ever seen. When you see your breath on a cold day, even when you're bundled up like a first-grader at the bus stop, your body is losing both heat and moisture. That you're losing heat is bad enough, what's worse is that you're replacing it with the cold stuff that's outside.

In order for your lungs to utilize the oxygen that's in the air you breathe, that air has to be warm and moist by the time it reaches your lungs. Cold air poaches this necessary warmth and moisture as it travels through your body, causing your core temperature to drop. Your body then reacts in a very quick and predictable way: It pulls blood from your extremities in order to keep your vital organs toasty. By storing the heat and water molecules from your exhaled breath in a "thermal exchanger" inside the mask, this Darth Vader-esque contraption recycles what your body would normally lose, maintaining your core temperature and keeping you warm all over. Sound like anatomy class babble? Maybe, but I tried it and it works. $60; 800-967-9727; www.polarwrap.com